Constraints on primordial black holes from the first part of LIGO-Virgo-KAGRA fourth observing run
arXiv:2605.15749
The paper uses data from the first part of the LIGO‑Virgo‑KAGRA O4 run to place the strongest limits to date on the fraction of dark matter that can be in primordial black holes across a wide mass range, employing new data‑driven methods that do not rely on assumptions about the astrophysical black‑hole population.
Abstract
We analyse primordial black hole (PBH) populations using state-of-the-art modelling of PBH binaries, deriving the strongest bounds on PBH abundance in the - range from LIGO-Virgo-KAGRA O4a data and demonstrating sensitivity in the - range, for both monochromatic and log-normal mass functions. The constraints are dominated by resolvable PBH mergers, while the associated gravitational wave background provides complementary but weaker limits. To obtain limits that are agnostic about the astrophysical black hole (ABH) population, we devise two new methods, data-driven methods for statistical inference on scenarios in which PBHs account for a subset of the catalogued events. Allowing for this possibility relaxes slightly the bounds in the solar mass range -. Our bounds are independent of the assumptions about the astrophysical black holes population and represent the most stringent constraints on the PBH abundance in the solar mass range to date.